The primary aim of the present study is to determine the impact of being an only child compared with having siblings (older, younger, or both; same or opposite sex) upon interpersonal competence and interpersonal orientation in late adolescence. Specifically, the project will determine the impact of family constellation upon global measures of competence, empathy, androgynous sex role development, additional personality characteristics, and orientations toward family, toward privacy, and toward adults versus peers. Secondary aims include a determination of variations in family cohesion, family interaction patterns, and parenting styles as a function of family constellation.